Hay and the other options...

The expressions “there is” or “there are” to indicate existence are “hay.” Furthermore, “¿hay?” also is used for “is there?” or “are there?”

“Hay” comes from the verb haber and its past forms for “was there” and “were there” can be either “había” or “hubo.” Preferable use “hubo” for events or activities or anything that happens or takes place. “Había” can be used for everything else.

i.e. Anoche hubo una fiesta. Había mucha comida en la fiesta.

“There will be” is “habrá” and “there would be” is “habría.”

More complex or creative constructions are:

1) There is/are going to be = va a haber
2) There has/have to be = tiene que haber
3) There can be = puede haber
4) There has/have been = ha habido

The subjunctive forms are “haya” or “hubiera/hubiese.”

There is another use with this haber form used to indicate obligation. This will be covered at a later posting.